U.S. patent application number 11/528664 was filed with the patent office on 2007-03-29 for developing device.
This patent application is currently assigned to BROTHER KOGYO KABUSHIKI KAISHA. Invention is credited to Mitsuru Horinoe, Yuichi Matsushita, Hiroki Mori, Yukiko Nakaya.
Application Number | 20070071490 11/528664 |
Document ID | / |
Family ID | 37894138 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070071490 |
Kind Code |
A1 |
Nakaya; Yukiko ; et
al. |
March 29, 2007 |
Developing device
Abstract
A developing device is provided with a case main body, a
developing roller coupled with the case main body, an axis
direction seal member coupled with the case main body, and a side
seal member coupled with the case main body. The axis direction
seal member and the side seal member make contact with one another
such that there is no gap between the axis direction seal member
and the side seal member in a rotation axis direction of the
developing roller. In a rotation direction of the developing
roller, an upstream end of the side seal member is located
downstream of an upstream end of a contact area between the axis
direction seal member and the developing roller.
Inventors: |
Nakaya; Yukiko; (Konan-shi,
JP) ; Horinoe; Mitsuru; (Chita-gun, JP) ;
Mori; Hiroki; (Nagoya-shi, JP) ; Matsushita;
Yuichi; (Nagoya-shi, JP) |
Correspondence
Address: |
BANNER & WITCOFF, LTD.;ATTORNEYS FOR CLIENT NOS. 0166889, 006760
1001 G STREET, N.W., 11TH FLOOR
WASHINGTON
DC
20001-4597
US
|
Assignee: |
BROTHER KOGYO KABUSHIKI
KAISHA
Nagoya-shi
JP
|
Family ID: |
37894138 |
Appl. No.: |
11/528664 |
Filed: |
September 28, 2006 |
Current U.S.
Class: |
399/103 |
Current CPC
Class: |
G03G 15/0817
20130101 |
Class at
Publication: |
399/103 |
International
Class: |
G03G 15/08 20060101
G03G015/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2005 |
JP |
2005-282636 |
Claims
1. A developing device, comprising: a case main body comprising an
opening; a developing roller coupled with the case main body at a
position facing the opening, the developing roller configured to
rotate and support a developer housed in the case main body; an
axis direction seal member coupled with the case main body, the
axis direction seal member extending along a rotation axis
direction of the developing roller, the axis direction seal member
sealing between the case main body and the developing roller by
making contact with the developing roller; and a side seal member
coupled with the case main body, the side seal member sealing
between the case main body and an end portion of the developing
roller in the rotation axis direction by making contact with the
end portion of the developing roller, wherein the axis direction
seal member and the side seal member make contact with one another
such that there is no gap between the axis direction seal member
and the side seal member in the rotation axis direction, and in a
rotation direction of the developing roller, an upstream end of the
side seal member is located downstream of an upstream end of a
contact area between the axis direction seal member and the
developing roller.
2. The developing device as in claim 1, wherein the axis direction
seal member comprises a first member and a second member, the first
member extends along the rotation axis direction and makes contact
with the developing roller, and the second member is located
between an end portion of the first member in the rotation axis
direction and the case main body.
3. The developing device as in claim 2, wherein, in the rotation
direction, the second member extends downstream beyond the first
member, the second member and the side seal member make contact
with one another such that there is no gap between the second
member and the side seal member in the rotation axis direction, and
in the rotation direction, the upstream end of the side seal member
is located between a downstream end of the first member and a
downstream end of the second member.
4. The developing device as in claim 2, wherein, the second member
extends outward beyond the first member in the rotation axis
direction, the second member and the side seal member make contact
with one another such that there is no gap between the second
member and the side seal member in the rotation axis direction, and
a gap is arranged between the first member and the side seal member
in the rotation axis direction.
5. The developing device as in claim 2, wherein, a coefficient of
friction of the first member is smaller than a coefficient of
friction of the second member.
6. The developing device as in claim 2, wherein the second member
is formed from felt or sponge.
7. The developing device as in claim 1, wherein, in the rotation
direction, the upstream end of the side seal member is located
between the upstream end of the contact area and a downstream end
of the axis direction seal member.
8. The developing device as in claim 7, wherein, in the rotation
direction, the upstream end of the side seal member is located
between the upstream end of the contact area and a downstream end
of the contact area.
9. The developing device as in claim 1, wherein, in the rotation
direction, the upstream end of the side seal member is located
downstream of a downstream end of the contact area.
10. The developing device as in claim 9, wherein, in the rotation
direction, the upstream end of the side seal member is located
between the downstream end of the contact area and a downstream end
of the axis direction seal member.
11. The developing device as in claim 1, wherein the case main body
further comprises a developer receiver located adjacent to an end
portion of the axis direction seal member in the rotation axis
direction.
12. The developing device as in claim 1, wherein the developer is a
non-magnetic mono-component polymerization toner.
13. The developing device as in claim 1, wherein the developing
device is a developer cartridge that is detachably mounted on an
image forming device that forms an image by utilizing the
developer.
14. A process cartridge that is detachably mounted on an image
forming device that forms an image by utilizing a developer, the
process cartridge comprising: a photoreceptor and the developing
device as in claim 1, wherein the developer supported by the
developing roller of the developing device is supplied to a surface
of the photoreceptor.
15. An image forming device that forms an image on a recording
medium by utilizing a developer, the image forming device
comprising: a photoreceptor and the developing device as in claim
1, wherein the developer supported by the developing roller of the
developing device is supplied to a surface of the photoreceptor,
and the developer supplied to the surface of the photoreceptor is
transferred to the recording medium.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Japanese Parent
Application No. 2005-282636, filed on Sep. 28, 2005, the contents
of which are hereby incorporated by reference into the present
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a developing device that
houses developer such as toner. In addition, the present invention
relates to a process cartridge and an image forming device.
[0004] 2. Description of the Related Art
[0005] A laser printer, for example, uses a developer to print on a
recording medium (e.g., printing paper). The laser printer has a
developing device. The developing device has a case main body in
which an opening is formed. A developing roller is coupled with the
case main body at a position that faces the opening. The developing
roller is capable of rotating and supporting the developer that is
housed in the case main body. The laser printer has a photoreceptor
that makes contact with the developing roller. An electrostatic
latent image is formed on the surface of the photoreceptor. By
rotating both the developing roller and the photoreceptor while in
contact with each other, the developer supported by the developing
roller adheres to the electrostatic latent image on the
photoreceptor In this way, the electrostatic latent image on the
photoreceptor becomes visible. By transferring the developer from
the photoreceptor to the recording medium, text or image is printed
on the recording medium.
[0006] If the developer housed in the developing device leaks to
the exterior, devices disposed at the exterior of the developing
device becomes soiled. It is necessary to form a developing device
from which developer cannot leak. In the technology disclosed in
U.S. Pat. No. 6,336,014, an axis direction seal member is installed
on the case main body. The axis direction seal member extends along
the rotation axis direction of the developing roller. By placing
the axis direction seal member in contact with the developing
roller, the axis direction seal member creates a seal between the
case main body and the developing roller. In addition, in the
technology of U.S. Pat. No. 6,336,014, a side seal member is used.
The side seal member makes contact with the developing roller so
that developer does not leak from the end of the developing roller
in the rotation axis direction. In this way, a seal is formed
between the end of the developing roller in the rotation axis
direction and the case main body. The axis direction seal member
and the side seal member make contact with one another. In this
configuration, a gap is not formed between the axis direction seal
member and the side seal member, and thus developer can be
prevented from leaking out from between the axis direction seal
member and the side seal member
[0007] Note that in the above conventional technology, in the
rotation direction of the developing roller, the upstream end of
the side seal member is located upstream of a contact area between
the axis direction seal member and the developing roller. In other
words, the side seal member makes contact with the axis direction
seal member at a position which is upstream of the contact area
between the axis direction seal member and the developing
roller.
BRIEF SUMMARY OF THE INVENTION
[0008] If developer enters between the side seal member and the
case main body, this developer may leak from the case main body.
Because of this, it is preferred that developer is prevented from
entering between the side seal member and the case main body.
[0009] In this specification, a developing device which can prevent
developer from leaking out is disclosed. This developing device
comprises a case main body, a developing roller, an axis direction
seal member, and a side seal member. In a rotation direction of the
developing roller, an upstream end of the side seal member is
located downstream of an upstream end of a contact area between the
axis direction seal member and the developing roller.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a cross-sectional view of a laser printer of
the present embodiment.
[0011] FIG. 2 shows an expanded cross-sectional view of a process
cartridge.
[0012] FIG. 3 shows a cross-sectional view of a photoreceptor
cartridge.
[0013] FIG. 4 shows a front view of a developer cartridge viewed
from the IV direction of FIG. 2.
[0014] FIG. 5 shows a perspective view of an end part of the
developer cartridge.
[0015] FIG. 6 shows a cross-sectional view along the line VI-VI of
FIG. 5
[0016] FIG. 7 shows a simplified front view of a side seal member
and an axis direction seal member.
[0017] FIG. 8 shows a simplified front view of a side seal member
and an axis direction seal member (Variant 1).
[0018] FIG. 9 shows a simplified front view of a side seal member
and an axis direction seal member (Variant 2).
[0019] FIG. 10 shows a simplified front view of a side seal member
and an axis direction seal member (Variant 3).
EMBODIMENT
[0020] An embodiment of the present invention will be described
with reference to the drawings. FIG. 1 is a cross-sectional view of
a laser printer 10 of the present embodiment. The laser printer 10
will be hereinafter referred to as printer 10. In the present
embodiment, the right side of FIG. 1 is the front of the printer
10.
[0021] The printer 10 has a casing 12. The casing 12 is constructed
by means of a plurality of plate-shaped members. FIG. 1 shows a
rear side cover member 14, a front side cover member 16, and the
like as members that constitute the casing 12. The front side cover
member 16 can pivot in the direction of the arrow R1 or the arrow
R2 with an axis 18 at the center. The casing 12 will open when the
front side cover member 16 pivots in the direction of the arrow R1.
A process cartridge 40 (described below) can be exchanged in this
state. The casing 12 will close when the front side cover member 16
pivots in the direction of the arrow R2.
[0022] The printer 10 has a paper supply device 20, the process
cartridge 40, an exposure device 70, a toner fixing device 90, and
the like. Each of the devices 20, 40, 70, 90 is disposed in the
interior of the casing 12. Each device 20, 40, 70 and 90 will be
described in sequence below.
[0023] The paper supply device 20 comprises a paper supply tray 22,
four rollers 28, 30, 32, 34, and the like. Paper for printing (not
shown in the drawings) will be stacked in the paper supply tray 22.
The paper supply tray 22 has a bottom plate 24 on which the stacked
printing paper will be placed. The uppermost sheet of the printing
paper placed on the bottom plate 24 will be in contact with the
paper supply roller 28. When the paper supply tray 22 is housed
inside the casing 12, the front end of the bottom plate 24 (the end
on the right side of FIG. 1) will be urged upward by a mechanism
not shown in the drawings. Thus, when the number of sheets of
printing paper is reduced, the front end of the bottom plate 24
will be raised upward. Because of this construction, the uppermost
sheet of the printing paper can always be placed in contact with
the paper supply roller 28.
[0024] The paper supply roller 28 is connected to a drive source
not shown in the drawings. The paper supply roller 28 can be
rotated counterclockwise. The uppermost sheet of printing paper
stored in the paper supply tray 22 will be transported to the right
(arrow D1) when the paper supply roller 28 rotates. The printing
paper transported to the right will come into contact with the
separation roller 30. The separation roller 30 is not connected to
a power source. The separation roller 30 is driven counterclockwise
by coming into contact with the printing paper. When a plurality of
sheets of printing paper has been transported, the separation
roller 30 will separate the printing paper so that only one sheet
thereof will be transported downstream. The printing paper that
passes the separation roller 30 will then be transported between
the pinch roller 32 and the paper dust removal roller 34.
[0025] The pinch roller 32 and the paper dust removal roller 34 are
not connected to a drive source. The pinch roller 32 is urged
toward the paper dust removal roller 34 by an urging means not
shown in the drawings. The printing paper between the pinch roller
32 and the paper dust removal roller 34 will be pressed onto the
paper dust removal roller 34 by the pinch roller 32. The surface of
the paper dust removal roller 34 has been specially treated, and
can remove paper dust from the printing paper that it is in contact
with. The printing paper will be transported between two resist
rollers 38, 38 along a rail 36.
[0026] The lower resist roller 38 is connected to a drive source
not shown in the drawings. The printing paper can be transported in
the direction of arrow D2 by rotating the lower resist roller 38
counterclockwise. The upper resist roller 38 rotates in the
clockwise direction by following the rotation of the lower resist
roller 38.
[0027] Text or images is printed on the printing paper when the
printing paper is transported in the direction of the arrow D2 by
the resist roller 38. More specifically, printing will be performed
by means of the process cartridge 40, the exposure device 70, and
the fixing device 90.
[0028] The process cartridge 40 is detachably mounted on the casing
12. The process cartridge 40 can be removed from the casing 12 when
the front cover 16 is opened (arrow R1). An old process cartridge
40 can be replaced with new one.
[0029] Details of the structure of the process cartridge 40 will be
described below. The basic structure of the process cartridge 40
will be described here. The process cartridge 40 has a casing 42. A
through hole 42a is formed in the upper surface of the casing 42. A
toner chamber 45 is formed on the right side of the interior of the
casing 42. Toner is housed in the toner chamber 45. Three rollers
48, 50, 52 and a photoreceptor drum 54 are disposed on the left
side of the interior of the casing 42. The rollers 48, 50, 52 and
the drum 54 are respectively connected to a drive source not shown
in the drawings. The roller 48 positioned furthest to the right
will be referred to as the supply roller. The developing roller 50
is disposed on the left side of the supply roller 48. The
photoreceptor drum 54 is disposed on the left side of the
developing roller 50. The transfer roller 52 is disposed below the
photoreceptor drum 54. Printing paper that has been transported in
the direction of the arrow D2 by the resist roller 38 will enter
between the photoreceptor drum 54 and the transfer roller 52. The
transfer roller 52 will rotate in the counterclockwise direction
when the photoreceptor drum 54 rotates in the clockwise direction.
The printing paper will be transported further leftward (arrow D2)
by rotating the photoreceptor drum 54 and the transfer roller 52.
Toner attached to the photoreceptor drum 54 will be transferred to
the printing paper as it is transported leftward.
[0030] The exposure device 70 is disposed above the process
cartridge 40. The exposure device 70 is fixed to the casing 12. The
exposure device 70 has a casing 72. A through hole 72a is formed in
the lower surface of the casing 72. A polygon mirror 74, a
reflector 76, a lens 78, a reflector 80, and the like are provided
inside the casing 72. The exposure device 70 has a light source
that is not shown in the drawings. A laser beam will be generated
from the light source based upon the content of the print data. The
laser beam supplied from the light source will be deflected by the
polygon mirror 74 toward the reflector 76. The laser beam will
reflect off the reflector 76 and pass through the lens 78. The
laser beam that has passed through the lens 78 will be further
reflected by the reflector 80. The laser beam reflected by the
reflector 80 will exit the casing 72 from the through hole 72a and
project downward.
[0031] The laser beam that has exited the casing 72 will pass
through the through hole 42a of the casing 42 of the process
cartridge 40 and arrive at the photoreceptor drum 54. In this way,
the photoreceptor drum 54 will be exposed with a prescribed
pattern. The path of the laser beam described above is shown with
the arrow L in FIG. 1.
[0032] Next, the structure of the toner fixing device 90 will be
described. The toner fixing device 90 is disposed to the rear of
the process cartridge 40 (the left side of FIG. 1). The toner
fixing device 90 comprises a frame 92, a heating roller 94, and a
pressure roller 96. The frame 92 supports the heating roller 94 and
the pressure roller 96 in a manner allowing rotation.
[0033] The heating roller 94 has a metal pipe 94a, and a halogen
lamp 94b that is disposed in the interior thereof. The halogen lamp
94b will heat the metal pipe 94a. The heating roller 94 is
connected to a drive source not shown in the drawings. When the
drive source is operated, the heating roller 94 will rotate in the
clockwise direction. The pressure roller 96 is urged toward the
heating roller 94 by means of a mechanism not shown in the
drawings. The pressure roller 96 is not connected to a drive
source. The pressure roller 96 will be driven in the
counterclockwise direction when the heating roller 94 is rotated in
the clockwise direction.
[0034] The printing paper that has passed through the process
cartridge 40 will be inserted between the heating roller 94 and the
pressure roller 96. When the heating roller 94 rotates in the
clockwise direction, the printing paper between the heating roller
94 and the pressure roller 96 will be transported leftward. The
printing paper will be heated by means of the heating roller 94
that has been heated to a high temperature. In this way, the toner
transferred to the printing paper will be fixed thereto by means of
heat. The printing paper that has passed through the toner fixing
device 90 will be transported upward and to the left (arrow
D3).
[0035] A transport roller 97 is disposed immediately below the left
end of the frame 92. The transport roller 97 is supported by the
casing 12. The transport roller 97 is connected to a drive source
not shown in the drawings. The transport roller 97 will rotate in
the counterclockwise direction. The transport roller 97 will
transport the printing paper transported from the toner fixing
device 90 further upward and to the left. The printing paper
transported upward and to the left by the transport roller 97 will
be transported rightward along a rail 98.
[0036] Two discharge rollers 100, 100 are disposed on the right
side of the rail 98. The lower discharge roller 100 is connected to
a drive source not shown in the drawings. The lower discharge
roller 100 will rotate in the clockwise direction. The upper
discharge roller 100 is not connected to a power source. When the
lower discharge roller 100 rotates in the clockwise direction, the
upper discharge roller 100 rotates in the counterclockwise
direction.
[0037] The printing paper transported by the transport roller 97 is
inserted between the two discharge rollers 100, 100. When the lower
discharge roller 100 rotates in the clockwise direction, the
printing paper between the two discharge rollers 100, 100 is
transported rightward. The printing paper is transported out of the
casing 12. A discharge tray 110 is formed on the upper surface of
the casing 12. The printing paper transported out of the casing 12
is discharged onto the discharge tray 110.
[0038] The basic structure of the printer 10 has been described.
How the printing paper is transported inside the casing 12 has been
described. Next, the detailed structure of the process cartridge 40
will be described with reference to FIG. 2. FIG. 2 shows an
enlarged cross-section of the process cartridge 40.
[0039] The process cartridge 40 is constructed by two cartridges
43, 44. The cartridge 43 disposed on the right side will be
referred to as a developer cartridge, and the cartridge 44 disposed
on the left side will be referred to as a photoreceptor cartridge.
The developer cartridge 43 and the photoreceptor cartridge 44 are
connected in a manner allowing separation. FIG. 3 shows a
cross-section of the photoreceptor cartridge 44 after the developer
cartridge 43 was separated. This process cartridge 40 allows only
the developer cartridge 43 to be exchanged, and also allows only
the photoreceptor cartridge 44 to be exchanged. The entire process
cartridge 40 can also be exchanged.
[0040] The structure of the two cartridges 43, 44 will be described
below. First, the structure of the photoreceptor cartridge 44 will
be described. The photoreceptor cartridge 44 has a casing 44a. The
through hole 42a through which a laser beam will pass is formed in
the upper surface of the casing 44a. An entrance hole 44b through
which printing paper will enter is formed in the lower surface of
the casing 44a. In addition, an exit hole 44c through which
printing paper will exit is formed in the left side surface of the
casing 44a. The printing paper enters into the photoreceptor
cartridge 44 from the entrance hole 44b, passes between the
photoreceptor drum 54 and the transfer roller 52, and exits from
the exit hole 44c.
[0041] The photoreceptor drum 54, the transfer roller 52, and a
charger 66 are disposed inside the casing 44a of the photoreceptor
cartridge 44.
[0042] The photoreceptor drum 54 is in contact with the developing
roller 50 on the left side of the developing roller 50. The
photoreceptor 54 has a photoreceptor drum main body 54a and a
photoreceptor drum shaft 54b. The photoreceptor drum main body 54a
has a tubular shape. The photoreceptor drum main body 54a is a
positive charge type photoreceptor. The surface of the
photoreceptor drum main body 54a is constructed by polycarbonate or
the like. The photoreceptor drum shaft 54b is made of metal. The
photoreceptor drum shaft 54b is fixed to the casing 44a of the
photoreceptor cartridge 44. The photoreceptor drum main body 54a is
attached to the photoreceptor drum shaft 54b. The photoreceptor
drum main body 54a is connected to a drive source not shown in the
drawings. The photoreceptor drum main body 54a rotates in the
clockwise direction.
[0043] The transfer roller 52 is in contact with the photoreceptor
drum 54 on the lower side of the photoreceptor drum 54. The
transfer roller 52 comprises a transfer roller main body 52a and a
transfer roller shaft 52b. The transfer roller main body 52a is
made of a conductive rubber material. The transfer roller shaft 52b
is made of metal. The transfer roller shaft 52b is attached to the
casing 44a of the photoreceptor cartridge 44. The transfer roller
shaft 52b is connected to a drive source not shown in the drawings.
The transfer roller 52 rotates in the counterclockwise direction.
The transfer roller shaft 52b is connected to a voltage supply
circuit not shown in the drawings. During transfer (during the time
in which the toner adhered to the photoreceptor drum 54 is
transferred to printing paper), a bias voltage will be applied from
the voltage supply circuit to the transfer roller 52.
[0044] The charger 66 is disposed above the photoreceptor drum 54.
A gap is arranged between the charger 66 and the photoreceptor drum
54. The charger 66 is a scorotron type. The charger 66 has a
discharge wire 66a and a grid 66b. The discharge wire 66a is a wire
that extends perpendicular to the plane of FIG. 2. A high voltage
will be applied to the discharge wire 66a. The grid 66b is disposed
between the discharge wire 66a and the photoreceptor drum 54. A
bias voltage will be applied to the grid 66b. In this way, the
amount of electric discharge of the discharge wire 66a is
regulated. A high voltage is applied to the discharge wire 66a and
a corona discharge will occur, and a bias voltage is applied to the
grid 66b. In this way, the surface of the photoreceptor drum 54
(the photoreceptor drum main body 54a) is provided with a positive
electrostatic charge.
[0045] Next, the structure of the developer cartridge 43 will be
described. The developer cartridge 43 has a case main body 43a. The
toner chamber 45 is formed inside the case main body 43a. Toner is
housed in the toner chamber 45. In the present embodiment, a
positive electrostatic charge type, non-magnetic mono-component
toner is used. For example, a polymer toner obtained by
co-polymerizing a styrene monomer and an acrylic monomer by means
of suspension polymerization will be used. Examples of acryl
monomers that can be used include acrylic acid, alkyl (C1-C4)
acrylate, alkyl (c1-C4) methacrylate, and the like. The polymer
toner is substantially spherical in shape, and has excellent
fluidity. A colorant and a wax are combined with the polymer toner.
In addition, in order to improve fluidity, an additive such as
silica or the like is added.
[0046] An agitator 46 is disposed in the toner chamber 45. The
agitator 46 is attached to the case main body 43a, and rotates with
a shaft 46a as a center. When the agitator 46 rotates in the
clockwise direction, the toner inside the toner chamber 45 is
agitated. In this way, the toner is supplied to the supply roller
48.
[0047] An opening 43b is formed in the left surface of the case
main body 43a. The opening 43b extends in a direction that is
perpendicular to the plane of FIG. 2. The supply roller 48 is
arranged on the right side of the opening 43b. The developing
roller 50 is arranged on the left side of the opening 43b.
[0048] The supply roller 48 comprises a supply roller main body 48a
and a supply roller shaft 48b. The supply roller main body 48a is
formed by means of a conductive foam material. The supply roller
shaft 48b is made of metal. The supply roller 48 is supported by
the case main body 43a of the developer cartridge 43. The supply
roller 48 is connected to a drive source not shown in the drawings.
The supply roller 48 rotates in the clockwise direction.
[0049] The developing roller 50 is in contact with the supply
roller 48 on the left side of the supply roller 48. The developing
roller 50 comprises a developing roller main body 50a and a
developing roller shaft 50b. The developing roller main body 50a is
made of a conductive rubber material. Examples of the rubber
material that can be used include a conductive urethane rubber or a
silicone rubber that contains carbon microparticles or the like.
The surface of the urethane rubber or the silicone rubber is coated
with a urethane rubber or a silicone rubber containing fluorine.
The developing roller shaft 50b is made of metal. The developing
roller shaft 50b is connected to a voltage supply circuit not shown
in the drawings. During development (during the time in which the
toner is adhered to the photoreceptor drum 54 from the developing
roller 50), a bias voltage is applied from the voltage supply
circuit to the developing roller 50. The developing roller 50 is
supported by the case main body 43a at a position that faces the
opening 43b. The developing roller 50 is connected to a drive
source not shown in the drawings. The developing roller 50 rotates
in the counterclockwise direction.
[0050] An adjustment member 47 is fixed to the case main body 43a.
The adjustment member 47 is arranged on the left side of the
opening 43b. The adjustment member 47 extends in a direction that
is perpendicular to the plane of FIG. 2, and is in contact with the
developing roller 50. In this way, the thickness of the developer
layer formed on the surface of the developing roller 50 is
regulated (adjusted).
[0051] FIG. 4 shows a simplified view of the developer cartridge 43
when viewed in the direction of line IV of FIG. 2. The developing
roller 50 is shown with a broken line in FIG. 4. The developing
roller 50 extends in the horizontal direction at a position that
faces the opening 43b of the case main body 43a. The adjustment
member 47 is fixed to the upper portion of the case main body 43a.
The adjustment member 47 extends in the horizontal direction
(rotation axis direction of the developing roller 50).
[0052] There are areas 140, 140 that face the rotation surface of
the developing roller 50 on both ends (right end and left end) of
the case main body 43a. In addition, there are areas 142, 142 that
face the rotation surface of the developing roller 50 on both ends
(right end and left end) of the adjustment member 47. The right
side facing area 140 of the case main body 43a and the right side
facing area 142 of the adjustment member 47 are aligned in the
vertical direction. Also, the left side facing area 140 and the
left side facing area 142 are aligned in the vertical direction. In
the rotation direction of the developing roller 50, the facing
areas 140, 140 of the case main body 43a are located upstream of
the facing areas 142, 142 of the adjustment member 47.
[0053] There are two side seal members 150, 150. One of the side
seal members 150 is bonded to the right side facing area 140 and
the right side facing area 142. The other of the side seal members
150 is bonded to the left side facing area 140 and the left side
facing area 142.
[0054] FIG. 5 shows a perspective view of the area around the right
end of the developer cartridge 43 (the right end of FIG. 4). The
structure of the right end of the developer cartridge 43 will be
described in detail. A detailed description of the left end of the
developer cartridge 43 will be omitted because it is a mirror image
of the right end of the developer cartridge 43. Note that FIG. 5
shows a portion of a frame member 160a (described below) cut away,
so that the structure of the adjustment member 47 will be clearly
understood.
[0055] The developing roller 50 is not shown in FIG. 5. A hole 143a
for supporting the developing roller 50 is provided in the right
end of the case main body 43a. The developing roller shaft 50b (see
FIG. 2) extends outward beyond the hole 143a (rightward in FIG.
5).
[0056] A front frame 143b is formed on the lower portion of the
case main body 43a. An axis direction seal member 156 is mounted on
the front frame 143b. The axis direction seal member 156 has an
axis direction seal portion 156a and a rotation direction seal
portion 156b. The axis direction seal portion 156a is a thin film,
and is formed from polyethylene terepthalate (PET). The axis
direction seal portion 156a extends along the rotation axis
direction of the developing roller 50. The axis direction seal
portion 156a extending along the rotation axis direction (the
horizontal direction) can be clearly seen in FIG. 4. In addition,
the axis direction seal portion 156a has a vertical width in a
range shown with the arrow S in FIG. 5. A part of the front frame
143b beyond the reference number 143c bends downwards. That is, the
front frame 143b curves downward. The axis direction seal portion
156a extends rearward beyond the portion 143c of the front frame
143. In other words, the axis direction seal portion 156a has a
floating portion that is not adhered to the front frame 143b. The
axis direction seal portion 156a and the front frame 143b are
adhered together by means of two-sided tape.
[0057] The rotation direction seal portion 156b is short along the
rotation axis direction of the developing roller 50, and long along
the rotation direction of the developing roller 50. The rotation
direction seal portion 156b is arranged between the outer end of
the axis direction seal portion 156a (the right end in FIG. 5) and
the front frame 143b. The rotation direction seal portion 156b is
bonded to the front frame 143b. The rotation direction seal portion
156b is formed from felt The rotation direction seal portion 156b
projects outward (to the right in FIG. 5) past the axis direction
seal portion 156a. The outer surface of the rotation direction seal
portion 156b is in contact with the inner surface of the side seal
member 150. In the present embodiment, the outer surface of the
axis direction seal portion 156a is not in contact with the inner
surface of the side seal member 150. A gap is arranged between the
outer surface of the axis direction seal portion 156a and the inner
surface of the side seal member 150.
[0058] The rotation surface of the developing roller 50 is in
contact with the axis direction seal portion 156a. In addition, the
rotation surface of the developing roller 50 is also in contact
with the portion of the rotation direction seal portion 156b that
projects out from the axis direction seal portion 156a. By placing
the developing roller 50 in contact with the axis direction seal
portion 156a and the rotation direction seal portion 156b, a seal
is created between the lower portion of the developing roller 50
and the case main body 43a.
[0059] Next, the structure of the side seal member 150 will be
described in detail with reference to FIG. 6. FIG. 6 shows a
cross-sectional view along line VI-VI of FIG. 5. Note that the
developing roller 50 is shown with a broken line in FIG. 6. The
arrow of the broken line indicates the rotation direction of the
developing roller 50.
[0060] The side seal member 150 has a case side elastic member
150a, an adjustment member side elastic member 150c , and a felt
member 150b. The case side elastic member 150a is bonded to the
facing area 140 of the case main body 43a (see FIG. 4). The
adjustment member side elastic member 150c is bonded to the facing
area 142 of the adjustment member 47 (see FIG. 4). The felt member
150c is bonded to both the case side elastic member 150a and the
adjustment member side elastic member 150c. The felt member 150b is
in contact with the rotation surface of the developing roller 50.
In this way, the end (right end of FIG. 4) of the developing roller
50 is sealed.
[0061] The felt member 150b extends leftwards (upstream side of the
rotation direction of the developing roller 50) beyond the case
side elastic member l50a The portion of the felt member 150b that
extends leftwards beyond the case side elastic member 150a is
bonded to the case main body 43a. The portion of the felt member
150b that is bonded to the case main body 43a is not in contact
with the developing roller 50. The portion of the felt member 150b
that is bonded to the case main body 43a does not function as a
seal for the developing roller 50. The portion indicated with
reference number 150d is the upstream end of the portion that
functions as a seal for the side seal member 150. The position
indicated with reference numeral 150d will be referred to below as
the upstream end of the side seal member 150.
[0062] As shown in FIG. 5, the side seal member 150 is thicker than
the axis direction seal member 156. The upper surface of the side
seal member 150 (the surface on the developing roller 50 side) is
in a position that is higher than the upper surface of the axis
direction seal member 156.
[0063] Next, the structure of the adjustment member 47 will be
described in detail. The adjustment member 47 has a support member
160. The support member 160 supports a contact member 162 that
makes contact with the developing roller 50. The contact member 162
is not visible in the cross-sectional view of FIG. 6, but is shown
in FIG. 5. The contact member 162 extends along the rotation axis
direction of the developing roller 50, and is in contact with
substantially the entire area of the developing roller 50 along the
rotation axis direction thereof. The contact member 162 is made of
rubber. The support member 160 is formed from two frame members
160a, 160b and a stainless steel plate 160c. The front side frame
member 160a (the left side of FIG. 6) is substantially L-shaped.
The stainless steel plate 160c is interposed between the front side
frame member 160a and the rear side frame member 160b. The two
frame members 160a, 160b and the stainless steel plate 160c
respectively extend along the rotation axis direction of the
developing roller 50 (in the direction perpendicular to the plane
of FIG. 6). As shown in FIG. 5, the contact member 162 is bonded to
the stainless steel plate 160c. The contact member 162 is not
bonded to the ends (right end and left end of FIG. 4) of the
stainless steel plate 160c. The adjustment member side elastic
member 150c is bonded to this end.
[0064] A sponge member 164 is disposed between the case main body
43a and the rear side frame member 160b. The sponge member 164
extends along the rotation axis direction of the developing roller
50. The sponge member 164 creates a seal between the case main body
43a and the frame member 160b. A sponge member 166 is also disposed
between the sponge member 164 and the stainless steel plate 160c.
The sponge member 166 also extends along the rotation axis
direction of the developing roller 50, and functions as a seal.
[0065] An elastic member (e.g., a sponge) 168 that is embedded
around the supply roller shaft 48b is disposed on the lower portion
of the case main body 43a. The side seal member 150 (the case side
elastic member 150a) is also bonded to the sponge 168.
[0066] As shown in FIG. 5, a guard film 180 is arranged outward of
the axis direction seal member 156 (the right side of FIG. 5). The
guard film 180 is attached to the front surface 143e of the case
main body 43a. The guard film 180 extends from the front surface
143e of the case main body 43a to the front frame 143b. A space 182
is provided between the guard film 180 and the side seal member
150. The formation of the space 182 is also clearly seen in FIG. 6.
The space 182 functions as a toner receiver. How the toner receiver
182 functions will be described in detail below.
[0067] Next, the positional relationship between the axis direction
seal member 156 and the side seal member 150 will be described in
detail with reference to FIG. 7. FIG. 7 shows a simplified front
view of the axis direction seal member 156 and the side seal member
150.
[0068] An area 190 shown by hatching indicates the portion in which
the axis direction seal member 156 is in contact with the
developing roller 50. An imaginary line 190b indicates the upstream
end of the contact area 190 (the upstream end in the rotation
direction of the developing roller 50). An imaginary line 190a
indicates the downstream end of the contact area 190 (the
downstream end in the rotation direction of the developing roller
50). The rotation direction seal portion 156b projects outward (to
the right in FIG. 7) more than the axis direction seal portion
156a. The rotation direction seal portion 156b is in contact with
the developing roller 50 at the projecting portion.
[0069] The central portion of the contact area 190 in the
horizontal direction is shallower than the end portions of the
contact area 190. That is, the upstream end 190b of the contact
area 190 extends in a straight line along the rotation axis
direction in the central portion of the developing roller 50, and
the outer ends thereof are curved on the upstream side (the lower
side of FIG. 7). In addition, the downstream end 190a of the
contact area 190 extends in a straight line along the rotation axis
direction in the central portion of the developing roller 50, and
the outer ends thereof are curved on the downstream side (the upper
side of FIG. 7). The central portion of the upstream end 190b of
the contact area 190 (the portion that extends in a straight line)
is located downstream of the downstream end 143c of a bonding area
between the front frame 143b (see FIG. 5) and the axis direction
seal portion 156a. In the present embodiment, the upstream end 150d
of the side seal member 150 is located between the upstream end
190b of the contract area 190 and the downstream end of the axis
direction seal member 156 (the axis direction seal portion 156a).
More specifically, the upstream end 150d of the side seal member
150 is located between the upstream end 190b and the downstream end
190a of the contract area 190. The upstream end 150d of the side
seal member 150 is located downstream (the upper side of FIG. 7) of
the central portion (the portion that extends in a straight line)
of the upstream end 190b of the contact area 190. The side seal
member 150 is not disposed upstream of the contact area 190.
[0070] The outer surface 156c of the rotation direction seal
portion 156b is in contact with the inner surface 150e of the side
seal member 150. A gap is arranged between the outer surface 156d
of the axis direction seal portion 156a and the inner surface 150e
of the side seal member 150.
[0071] The structure of the process cartridge 40 has been described
in detail. Referring again to FIG. 2, the operation of the process
cartridge 40 having the aforementioned structure will be
described.
[0072] The toner of the toner chamber 45 adheres to the supply
roller 48. The toner adhered to the supply roller 48 is positively
charged by means of friction between the supply roller 48 and the
developing roller 50. The toner that is positively charged covers
the surface of the developing roller SO. The contact member 162 of
the adjustment member 47 (see FIG. 5) makes contact with the toner
layer on the surface of the developing roller 50. In this way, the
toner layer is adjusted to a uniform thickness.
[0073] In contrast, the surface of the photoreceptor drum main body
54a is positively charged by means of the charger 66. The surface
of the positively charged photoreceptor drum main body 54a is
irradiated with a laser beam generated from the exposure device 70
(see FIG. 1). In this way, a predetermined portion of the surface
of the photoreceptor drum main body 54a is thus exposed. The
electric potential of the exposed portion of the photoreceptor drum
main body 54a is reduced. The part that is exposed varies based on
the content to be printed. An electrostatic latent image based upon
the print content is formed on the photoreceptor drum main body
54a.
[0074] The toner that covers the developing roller 50 adheres to
the exposed portion of the photoreceptor drum main body 54a. At
this point, the toner does not adhere to the non-exposed portion of
the photoreceptor drum main body 54a. In this way, the
electrostatic latent image formed on the photoreceptor drum main
body 54a becomes visible. A visible image having a uniform
thickness is developed on the photoreceptor drum main body 54a
because the thickness of the toner layer on the developing roller
50 is uniformly maintained by means of the adjustment member
47.
[0075] The visible image supported on the photoreceptor drum main
body 54a is transferred to printing paper between the photoreceptor
drum 54 and the transfer roller 52. At this point, a bias voltage
is applied to the transfer roller 52. The toner is transferred to
the printing paper due to the difference in electric potential
between the photoreceptor drum 54 and the transfer roller 52. The
toner is transferred to the printing paper at a uniform density
because a visible image having a uniform thickness is developed on
the photoreceptor drum main body 54a. In this way, the printing
density is uniformly maintained.
[0076] A desired image (text or drawing) is printed on the printing
paper by means of each of the aforementioned processes.
[0077] The axis direction seal portion 156a shown in FIG. 7 is
formed from polyethylene terepthalate (PET), and thus has a lower
coefficient of friction than the rotation direction seal portion
156b. The present inventors discovered that when the developing
roller 50 is rotated between each process described above, and the
toner adheres to an area which is located upstream of the contact
area 190, there is a tendency for the toner adhered to the axis
direction seal portion 156a to move outward (rightward in FIG. 7).
The arrow P in FIG. 7 shows the outward movement of the toner
adhered to the axis direction seal portion 156a. In the present
embodiment, the upstream end 150d of the side seal member 150 is
located between the upstream end l90b and the downstream end 190a
of the contract area 190. The side seal member 150 is not located
upstream of the contact area 190. Thus, the toner that has moved in
the direction of the arrow P will not reach the side seal member
150. The toner that has moved in the direction of arrow P is housed
in the toner receiver 182. In addition, because a gap is provided
between the axis direction seal portion 156a and the side seal
member 150, it is difficult for the toner that has moved in the
direction of the arrow P to move toward the side seal member 150.
According to the present embodiment, the toner that has moved in
the direction of the arrow P can be effectively prevented from
entering between the side seal member 150 and the case main body
43a.
[0078] Although a gap is provided between the axis direction seal
portion 156a and the side seal member 150, the outer surface 156c
of the rotation direction seal portion 156b is in contact with the
inner surface 150e of the side seal member 150. In this way, a seal
is created between the axis direction seal member 156 and the side
seal member 150. Toner can be prevented from leaking out from
between the axis direction seal member 156 and the side seal member
150.
[0079] In the present embodiment, the axis direction seal member
156 is formed by the axis direction seal portion 156a and the
rotation direction seal portion 156b. Because the rotation
direction seal portion 156b is provided, it is difficult for toner
on the right end or left end of the axis direction seal portion
156a to enter between the axis direction seal portion 156a and the
case main body 43a. Because of this, the sealing effect can be
further improved.
[0080] The sealing effect of the developer cartridge 43 of the
present embodiment is extremely high. If this developer cartridge
43 is used, soiling of the printer 10 by leaked toner can be
effectively prevented.
[0081] Specific examples of embodiments of the present invention
are presented above, but these merely illustrate some possibilities
of the invention and do not restrict the claims thereof. The
technique set forth in the claims includes transformations and
modifications to the specific examples set forth above.
[0082] For example, the side seal member 150 and the axis direction
seal member 156 can be modified as follows.
(Variant 1)
[0083] FIG. 8 shows a simplified front view of the side seal member
150 and the axis direction seal member 156 of the present
modification. In this modification, the rotation direction seal
portion 156b does not project outward (to the right in FIG. 8) more
than the axis direction seal portion 156a. In this case, the outer
surface 156d of the axis direction seal portion 156a is in contact
with the inner surface 150e of the side seal member 150. In
addition, the outer surface 156c of the rotation direction seal
portion 156b is in contact with the inner surface 150e of the side
seal member 150. In the present modification, the upstream end 150d
of the side seal member 150 is positioned between the upstream end
190b and the downstream end 190a of the contract area 190.
[0084] With this configuration, the developer cartridge 43 having a
highly effective seal can be achieved.
(Variant 2)
[0085] FIG. 9 shows a simplified front view of the side seal member
150 and the axis direction member 156 of the present modification.
In this modification, the rotation direction seal portion 156b
projects downstream (the upper side in FIG. 9) more than the axis
direction seal portion 156a. The rotation direction seal portion
156b does not project outward (to the right in FIG. 9) from the
axis direction seal portion 156a. The outer surface 156c of the
rotation direction seal portion 156b is in contact with the inner
surface 150e of the side seal member 150. In this modification, the
upstream end 150d of the side seal member 150 is located downstream
of the downstream end 190a of the contact area 190.
[0086] With this modification, a large space is formed between the
area that is located upstream of the contact area 190 and the
upstream end 150d of the side seal member 150. Thus, it is
difficult for toner that has moved in the direction of the arrow P
to reach the side seal member 150. According to the present
modification, a larger toner receiver 182 can be provided.
(Variant 3)
[0087] FIG. 10 shows a simplified front view of the side seal
member 150 and the axis direction member 156 of the present
modification. In this modification, the rotation direction seal
portion 156b projects downstream (the upper side in FIG. 10) more
than the axis direction seal portion 156a. In addition, the
rotation direction seal portion 156b projects outward (to the right
in FIG. 10) more than the axis direction seal portion 156a. The
rotational direction seal 156b is in contact with the developing
roller 50 at these projecting portions. The outer surface 156c of
the rotation direction seal portion 156b is in contact with the
inner surface 15Oe of the side seal member 150. In this
modification, the upstream end 150d of the side seal member 150 is
located downstream of the downstream end 190a of the contact area
190. The upstream end 150d of the side seal member 150 is located
between the downstream end 156e of the axis direction seal portion
156a and the downstream end 156f of the rotation direction seal
portion 156b.
[0088] With this configuration, a large space can be formed between
the area that is located upstream of the contact area 190 and the
upstream end 150d of the side seal member 150. In addition, a large
toner receiver 182 can be provided.
(Variant 4)
[0089] In the above embodiment, the rotation direction seal portion
156b is formed from felt. However, the rotation direction seal
portion 156b may be formed from another material. For example, the
rotation direction seal portion 156b may be formed from sponge.
[0090] In addition, the technical elements disclosed in the present
specification or figures may be utilized separately or in various
combinations and are not limited to the combination set forth in
the claims at the time of filing of this application. Furthermore,
the technique disclosed in the present specification or figures may
be utilized to simultaneously realize a plurality of objects or to
realize one of these objects.
* * * * *